1. Field of the Invention
The present invention relates to a multijoint manipulator which flexes joints by pulling wires, and an endoscope system having the same.
2. Description of the Related Art
A manipulator in which rods are joined by flexible joints is generally known as one arm-type robot. Various functional parts are attached to the distal end of such a manipulator in use depending on the purpose. A functional part can be, for example, a holder for holding an article. Inside the manipulator, wires coupled on one end to the joints are provided for flexing motion. As at least two wires are required for one joint, at least the number of wires twice the number of joints is required.
According to a configuration known as a technique for reducing the manipulator in weight, wires are wound and hung around a pulley so that the wires interfere with one another, thereby reducing the number of wires. Control of such a manipulator that uses wires requires a joint torque control system and a wire tension control system and is complex. For example, a technique that performs the following control is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 6-31662. According to this technique, a desired position for the displacement of the wires is first calculated from a target position of the distal end of the manipulator to be moved. Actual displacement of the wires is also measured. The desired position for the displacement of the wires is then compared with the actual displacement, and tension to be applied to the wires is found on the basis of the comparison to drive and control the manipulator.